The world and its leaders need more ambition and more realism. The ambition requires increasing the options available. Generous subsidies perpetuate today’s low-carbon technologies; the goal should be to usher in tomorrow’s. Unfortunately, energy companies (unlike, say, drug firms or car companies) see investment in radical new technologies as a poor prospect, and governments have been feeble in taking up the slack. A broad commitment quickly to raise and diversify R&D spending on energy technologies would be more welcome than more or less anything else Paris could offer.

This would be costly. But remember three things. One is that spending money to reduce grave risks is reasonable. The second is that some of today’s climate policies cost a lot more than a greatly expanded research portfolio and yield rather less. The subsidies that have created thousands of wind and solar farms have achieved only a little and at great cost. Other green subsidies, such as some of those for biofuels, have done actual harm. There is plenty of money to be saved.

A third is that one of the best measures against climate change raises money. Well-designed carbon prices can boost green power, encourage energy-saving and suppress fossil-fired power much more efficiently than subsidies for renewables. A few brave places have plumped to set such prices through carbon taxes: the latest is Alberta, in Canada. Most countries that have tried to price carbon have instead issued tradable pollution permits—invariably too many of them, with the result that the price is too low to change behaviour. Ideally such countries would admit their mistake and start taxing. Failing that, they should keep their emissions-trading schemes but add a floor price, and raise it steadily.

The new research agenda needs to tackle the deficiencies of renewables. Though solar, in particular, has become a lot cheaper, new materials, manufacturing and assembly technologies could make it cheaper still. Better ways of storing energy are required—so that wind or solar power can be used, for example, in the cold, still winter evenings when European electricity demand tends to peak. So are better ways of getting it from A to B, either through larger grids or in the form of newly synthesised fuels. Could biotechnology produce photosynthetic bugs that pump out lots of usable fuels? No one knows. It would be worth a few billion to find out.